Morus Alba Winter Pruning

Question from Ron:

This is our first year in new home with spendid landscaping near Lake Murray in La Mesa. Large morus alba has been pollarded over the years annually by previous owners. How close to “knuckles” should I cut the old growth back now that the tree is defoliated?

Answer from Pat:

Pollarding, as I’m sure you know, is a system of cutting certain trees in winter at the same place each year so they develop knobs on the ends of their scaffold branches. Hundreds of years ago pollarding, like copsing, which is a method of cutting trees, such as poplar, down to a “bench” which would then sprout again with several trunks, was developed as a method of harvesting useable wood for fodder, firewood or stakes from trees without killing the trees. Pollarding is still used today, especially in Europe, to keep trees low and provide an umbrella of dense shade along tow paths and roadways and to provide shade for cattle or for outdoor seating areas or simply for ornamental reasons. Pollarded trees are very stocky and strong and are almost never felled by storms. But only certain types of broadleaf trees are good for pollarding, these include sycamore or plane trees (Platanus), linden, beech, willow, and mulberry (Morus.) It does not work on trees, such as pines, that lack sufficient dormant buds under the bark.

The proper way to remove the lateral branches that grew from the knobs last year is to use a saw and make the cuts flush with the branch collar. Do not harm the branch collar so the cut can heal, but leave no stubs. The result of leaving stubs is uneven and even gruesome looking knobs or two and three knobs on the same branch. The best time to do this pruning is in autumn immediately after all leaves fall or in early winter while the tree is dormant. In olden times the cutting was often done in early fall while green leaves were still on the tree and these leafy twigs were used as fodder for farm animals during winter. Historically, if the twigs were to be used as fuel or to make wattle fencing, then the twigs were removed during winter. If the twigs were to be used as firewood or as garden stakes, sometimes farmers allowed a two or three years to go by before cutting off the straight branches that then were thicker. American books on tree management often preach against pollarding, but a correctly pollarded tree often lives longer than one that is allowed to grow in a natural manner.